SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38d6329dcd6f196986df415ca4467963a8b227051743d1917eaec7e027313fda' 
  AND token = 'hueMqhlPnRX73IWFdUuh3qkTJLNEkEB3aBoyp5yL/8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}